1. Field of the art
This invention relates to reinforcement of a thermoplastic resin composition with glass fibers. More particularly, the present invention relates to a glass fiber reinforced thermoplastic resin composition capable of giving a molded article endowed with both excellent rigidity and impact resistance, which composition is obtained by formulating a glass fiber obtained by use of a mixture of a specific polymer and a specific silane compound as a binder or a sizing agent in a resin mixture comprising a polyamide resin and an aromatic vinyl copolymer resin, and also to said glass fiber.
2. Related art
Polyamide resins have excellent properties in such as abrasion resistance, electrical characteristics, mechanical strength and chemical resistance, and their formed or molded products have been employed in the art as engineering plastics for various kinds of mechanical parts. These polyamide resins also have the drawbacks of great water absorption, and small impact resistance, particularly small notched impact strength. On the other hand, as compared with styrene polymers which are resins for general purpose, they have also the drawbacks of inferior heat resistance under high load and moldability. Since polyamide resins have such drawbacks, their uses as engineering plastics have been limited, and it has in some cases been found that the excellent characteristics inherent in polyamide resins are not fully enjoyed.
As the method for improving these drawbacks of polyamide resins, for example, it has been known to process them into blends with acrylonitrile-butadiene-styrene copolymers (ABS resin) (see, for example, Japanese Patent Publication No. 23476/1963). However, the blended composition of a polyamide resin and an ABS resin is inferior in compatibility of the both component resins, and when formed or molded into an article, there may appear such drawbacks that layered peeling phenomenon due to poor mixing occurs, or that the mechanical strength such as tensile strength is markedly lowered. For this reason, as the method for improving compatibility of a polyamide resin with a styrene resin such as ABS resin, it has been proposed to formulate a styrene polymer containing an .alpha., .beta.-unsaturated dicarboxylic acid anhydride as the third component into the blend of the both resins (see, for example, Japanese Patent Publication No. 47304/1985). By formulation of such third component, a resin composition with a polyamide resin and a styrene polymer physically finely dispersed in each other can be surely obtained. However, it appears that the impact resistance of the resin composition comprising the three components is not substantially improved.
Also, for enhancing the rigidity of these resins, there has been also a proposal about a resin composition in which glass fibers can be formulated (see, for example, Japanese Laid-open Patent Publication No. 165451/1988). However, it appears that only a resin composition with extremely low impact resistance has been obtained by mere formulation of the glass fibers as such.
As described above, in resin compositions of polyamide resins and styrene polymers, there may have been obtained no resin materials having excellent properties of the two resins, and also endowed with excellent rigidity and impact resistance under the present situation.
Glass fibers are known in the art as, for instance, reinforcing agents for plastics. Glass fibers are produced with the use of a binder or a sizing agent for preventing balooning of the as-spinned glass fibers or for affording the fibers desired characteristics.